Mouse permeability studies

Permeability Studies. A two-chamber diffusion cell procedure (8. 12) was employed with freshly excised hairless mouse skin. The diffusion cell consisted of two half cells or compartments (2 ml volume/half cell) and the area for diffusion between the two half cells was approximately 0.6 cm2. The full-thickness skin membrane was prepared by sacrificing the mouse as previously described and excising two square sections of the left and right abdominal skin. A skin membrane was mounted between the two compartments of the diffusion cell with the dermis side facing the receiver compartment, clamped and excess skin trimmed. The assembled diffusion cells were immersed in a water bath at the selected temperature between 10 and 60°C. Glycerine baths were used for temperatures between 60 and 90°C. Each compartment was filled with PBS adjusted to 7.3 pH at the specific experimental temperatures. 

Three examples will show how freezing processes can be studied quantitatively and documented using this microscope system. Figure 1.39 shows the change in volume of an isolated islet cell of a mouse as a function of temperature. The different permeability of cell membranes for HzO and CPAs are important for freezing of cell, as Fig. 1.40 shows. 

Table 8—Permeability rate of propranolol hydrochloride from Methocel matrix diffusion study through hairless mouse skin (comparative data)...

The nuclear envelope acts as a permeability barrier for a variety of macromolecules, and DNA is no exception. In 1980, Mario Capecchi demonstrated that when a pBR322-derived plasmid expressing thymidine kinase (TK) was microinjected into the nuclei of TK-deficient mouse fibroblasts, between 50% and 100% of the injected cells showed TK activity at 24 hours post-injection (Capecchi, 1980). By contrast, in over 1000 cytoplasmically injected cells, no gene expression was detected in any cell during the same time frame. Similar results were obtained in another microinjection study using rat TK-deficient cells and a plasmid expressing chloramphenicol acetyl transferase (CAT) driven by a herpes TK promoter. When 1000-2000 copies of the plasmid were injected into the cytoplasm, less than 3% of the activity was seen as compared to cells injected in the nucleus with the same number of plasmids (Graessman et al., 1989). Zabner et al. 

Studies from our lab have identified a calcium-permeable, voltage-independent channel, whose probability of opening is significantly greater in cultured myotubes derived from mdx mouse or human DMD tissue (Fong et al., 1990) and in isolated,... 

Thermally induced permeability enhancement of the more lipophilic solutes (butanol, octanol and hydrocortisone) through hairless mouse stratum corneum occurred in the temperature range also associated with lipid transitions in the calorimetry studies. Therefore, it seems likely enhanced permeabilities and lipid mobility within the stratum corneum are correlated. However, these macroscopic studies are unable to provide more specific information concerning the molecular origins of the thermal transitions. The studies provide even less information concerning possible irreversible alterations of the keratinized protein components of the stratum corneum. 

Pikal, M. and Shah, S. Transport mechanisms in iontophoresis III. An experimental study of the contributions of electro-osmotic flow and permeability change in transport of low and high MW solutes. Pharm. Res. 7 222, 1990. Gangerosa, L. P., Park, N.-H., Wiggins, C. A., and Hill, J. M. Increased penetration of non-electrolytes into mouse skin during iontophoretic water transport (lontohydrokinesis). J. Pharm. Exp. Ther. 212 311, 1980. 

Goodall, H. and Johnson, M. H. (1982). Use of carboxyfluorescein diacetate to study formation of permeable channels between mouse blastomeres. Nature 295, 524-526. 

The FVB-T1E2/GFP mouse, in which the endothelium is fluorescent, has heen used to study morphological changes in the renal microvascular endothelium during ischemia-reperfusion injury in the kidney [169]. Alterations in the cytoskeleton of renal microvascular endothelial cells correlated with a permeability defect in the renal microvasculature as identified using fluorescent dextrans and two-photon intravital imaging. This study demonstrates that renal vascular endothelial injury occurs in ischemic AKI and may play an important role in the pathophysiology of ischemic AKI. 

Stephens, R.H., Tanianis-Hughes, J., Higgs, N.B., Humphrey, M. and Warhurst, G. (2002) Region-dependent modulation of intestinal permeability by drug efflux transporters in vitro studies in mdrla(—/—) mouse intestine. The Journal of Pharmacology and Experimental Therapeutics, 303 (3), 1095-1101. 

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